Sexy! One way to smooth is to find the exact color you need to fill in the uneven space, then match the drawing tool to the same size and use the smoothing tool at 65% when you fill in the uneven places. Also use the soft round brush 5H! :)

You did a fantastic job already, so you don't seem to need much in the way of tips. I usually use fairly low opacity with the pen tool to lay down the colors followed by some low opacity airbrush to blend the two areas. The blend tool can help too.

you are already so amazing, and you just started on the site! wow. and... well to get smoother skin tones try and use more transparency in lighter and darker colours over a wider amount of space? i'm not sure. either way it is great. 5/5 :)